If you guys are having problems with different makes of ammo, I would really suggest ADJUSTING THE GAS BLEED COLLAR to compensate.
There should be no slam-fires with this rifle. If there are, it ain't the primer: it's the action taking too much gas OR not bleeding enough gas and operating too fast and hard. This was PRECISELY the problem with the ill-fated 555, the Tok, it is the problem with most AG-42B rifles and it is the problem with the FAL.
In each and every case, the problem is at the gas port.
With the FAL and the SAFN both, you screw the gas-adjustment one direction to OPEN the gas bleed, the other way to close it; you can see the angled front of the collar as it allows more or less gas to escape. Proper adjustment for any ammo is with the brass just coming out of the rifle and dropping on the bench beside you. This will give them the best accuracy, too. Combat adjustment was to set it the same, then go 1 click more CLOSED in order to assure functioning with the rifle slightly fouled. With the FAL, the gas-bleed adjustment sleeve is immediately behind the Gas Block on the top of the Barrel; it is in the same place on the SAFN, but you first must remove the Top Front Handguard to get at it.
There are different solutions for the other rifles; I have written on these in the past.
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